-
The Cochrane Database of Systematic... Feb 2016Graves' disease is the most common cause of hyperthyroidism. Both antithyroid medications and radioiodine are commonly used treatments but their frequency of use varies... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Graves' disease is the most common cause of hyperthyroidism. Both antithyroid medications and radioiodine are commonly used treatments but their frequency of use varies between regions and countries. Despite the commonness of the diagnosis, any possible differences between the two treatments with respect to long-term outcomes remain unknown.
OBJECTIVES
To assess the effects of radioiodine therapy versus antithyroid medications for Graves' disease.
SEARCH METHODS
We performed a systematic literature search in the Cochrane Library, MEDLINE and EMBASE and the trials registers ICTRP Search Portal and ClinicalTrials.gov. The date of the last search was September 2015 for all databases.
SELECTION CRITERIA
Randomised controlled trials (RCTs) comparing the effects of radioiodine therapy versus antithyroid medications for Graves' disease with at least two years follow-up.
DATA COLLECTION AND ANALYSIS
Two authors independently screened titles and abstracts for relevance. One author carried out screening for inclusion, data extraction and 'Risk of bias' assessment and a second author checked this. We presented data not suitable for meta-analysis as descriptive data. We analysed the overall quality of evidence utilising the GRADE instrument.
MAIN RESULTS
We included two RCTs involving 425 adult participants with Graves' disease in this review. Altogether 204 participants were randomised to radioiodine therapy and 221 to methimazole therapy. A single dose of radioiodine was administered. The duration of methimazole medication was 18 months. The period of follow-up was at least two years, depending on the outcome measured. For most outcome measures risk of bias was low; for the outcomes health-related quality of life as well as development and worsening of Graves' ophthalmopathy risks of performance bias and detection bias were high in at least one of the two RCTs.Health-related quality of life appeared to be similar in the radioiodine and methimazole treatment groups, however no quantitative data were reported (425 participants; 2 trials; low quality evidence). The development and worsening of Graves' ophthalmopathy was observed in 76 of 202 radioiodine-treated participants (38%) and in 40 of 215 methimazole-treated participants (19%): risk ratio (RR) 1.94 (95% confidence interval (CI) 1.40 to 2.70); 417 participants; 2 trials; low quality evidence. A total of 35% to 56% of radioiodine-treated participants and 42% of participants treated with methimazole were smokers, which is associated with the risk of worsening or development of Graves' ophthalmopathy. Euthyroidism was not achieved by any participant being treated with radioiodine compared with 64/68 (94%) of participants after methimazole treatment (112 participants; 1 trial). In this trial thyroxine therapy was not introduced early in both treatment arms to avoid hypothyroidism. Recurrence of hyperthyroidism (relapse) in favour of radioiodine treatment showed a RR of 0.20 (95% CI 0.01 to 2.66); P value = 0.22; 417 participants; 2 trials; very low quality evidence. Heterogeneity was high (I² = 91%) and the RRs were 0.61 or 0.06 with non-overlapping CIs. Adverse events other than development of worsening of Graves' ophthalmopathy for radioiodine therapy were hypothyroidism (39 of 41 participants (95%) compared with 0% of participants receiving methimazole, however thyroxine treatment to avoid hypothyroidism was not introduced early in the radioiodine group - 104 participants; 1 trial; very low quality evidence) and drug-related adverse events for methimazole treatment (23 of 215 participants (11%) reported adverse effects likely related to methimazole therapy - 215 participants; 2 trials; very low quality evidence). The outcome measures all-cause mortality and bone mineral density were not reported in the included trials. One trial (174 participants) reported socioeconomic effects: costs based on the official hospital reimbursement system in Sweden for patients without relapse and methimazole treatment were USD 1126/1164 (young/older methimazole group) and for radioiodine treatment USD 1862. Costs for patients with relapse and methimazole treatment were USD 2284/1972 (young/older methimazole group) and for radioiodine treatment USD 2760.
AUTHORS' CONCLUSIONS
The only antithyroid drug investigated in the two included trials was methimazole, which might limit the applicability of our findings with regard to other compounds such as propylthiouracil. Results from two RCTs suggest that radioiodine treatment is associated with an increased risk of Graves' ophthalmopathy. Our findings suggest some benefit from radioiodine treatment for recurrence of hyperthyroidism (relapse) but there is uncertainty about the magnitude of the effect size.
Topics: Antithyroid Agents; Graves Disease; Graves Ophthalmopathy; Humans; Iodine Radioisotopes; Methimazole; Randomized Controlled Trials as Topic; Recurrence
PubMed: 26891370
DOI: 10.1002/14651858.CD010094.pub2 -
Frontiers in Endocrinology 2022Methimazole (MMI) is the first-line treatment for patients with Graves' disease (GD). While there are empirical recommendations for initial MMI doses, there is no clear...
Mathematical Modeling of Free Thyroxine Concentrations During Methimazole Treatment for Graves' Disease: Development and Validation of a Computer-Aided Thyroid Treatment Method.
BACKGROUND
Methimazole (MMI) is the first-line treatment for patients with Graves' disease (GD). While there are empirical recommendations for initial MMI doses, there is no clear guidance for subsequent MMI dose titrations. We aimed to (a) develop a mathematical model capturing the dynamics of free thyroxine (FT4) during MMI treatment (b), validate this model by use of numerical simulation in comparison with real-life patient data (c), develop the software application Digital Thyroid (DigiThy) serving either as a practice tool for treating virtual patients or as a decision support system with dosing recommendations for MMI, and (d) validate this software framework by comparing the efficacy of its MMI dosing recommendations with that from clinical endocrinologists.
METHODS
Based on concepts of automatic control and by use of optimization techniques, we developed two first order ordinary differential equations for modeling FT4 dynamics during MMI treatment. Clinical data from patients with GD derived from the outpatient clinic of Endocrinology at the Medical University of Graz, Austria, were used to develop and validate this model. It was subsequently used to create the web-based software application DigiThy as a simulation environment for treating virtual patients and an autonomous computer-aided thyroid treatment (CATT) method providing MMI dosing recommendations.
RESULTS
Based on MMI doses, concentrations of FT4, thyroid-stimulating hormone (TSH), and TSH-receptor antibodies (TRAb), a mathematical model with 8 patient-specific constants was developed. Predicted FT4 concentrations were not significantly different compared to the available consecutively measured FT4 concentrations in 9 patients with GD (52 data pairs, p=0.607). Treatment success of MMI dosing recommendations in 41 virtually generated patients defined by achieved target FT4 concentrations preferably with low required MMI doses was similar between CATT and usual care. Statistically, CATT was significantly superior (p<0.001).
CONCLUSIONS
Our mathematical model produced valid FT4 predictions during MMI treatment in GD and provided the basis for the DigiThy application already serving as a training tool for treating virtual patients. Clinical trial data are required to evaluate whether DigiThy can be approved as a decision support system with automatically generated MMI dosing recommendations.
Topics: Antithyroid Agents; Computers; Graves Disease; Humans; Methimazole; Models, Theoretical; Thyroid Hormones; Thyroxine
PubMed: 35721705
DOI: 10.3389/fendo.2022.841888 -
Biomedicine & Pharmacotherapy =... Aug 20233,4-methylenedioxymethamphetamine (MDMA) is a popular recreational drug, however over 200 studies demonstrate that acute (e.g. hyperthermia, rhabdomyolysis) and chronic...
3,4-methylenedioxymethamphetamine (MDMA) is a popular recreational drug, however over 200 studies demonstrate that acute (e.g. hyperthermia, rhabdomyolysis) and chronic (e.g. neurotoxicity) toxicity effects of MDMA were observed in different animals. Methimazole (MMI), an inhibitor of thyroid hormone synthesis, was found to significantly reduce the HSP72 expression of heat stress induced in fibroblasts. Hence, we attempted to understand the effects of MMI on MDMA induced changes in vivo. Male SD rats were randomly divided into four groups as follows:(a) water-saline (b) water-MDMA (c) MMI-saline and (d) MMI-MDMA group. In the temperature analysis test, MMI was found to alleviate MDMA-induced hyperthermia and increase the heat loss index (HLI), revealing its peripheral vasodilation effect. PET experiment suggested that MDMA induced elevated glucose uptake by skeletal muscles, which was resolved by MMI pretreatment. IHC staining (serotonin transporter, SERT) showed the evidence of neurotoxicity caused by MDMA (serotonin fiber loss), which was alleviated by MMI. Furthermore, the animal behaviour test (forced swimming test, FST) showed higher swimming time but lower immobility time in MMI-MDMA and MMI-saline groups. Taken together, treatment of MMI shows benefits such as lowered body temperature, alleviation of neurotoxicity and excited behaviour. However, further investigations should be conducted in the future to provide in-depth evidence for its clinical use.
Topics: Rats; Male; Animals; N-Methyl-3,4-methylenedioxyamphetamine; Methimazole; Rats, Sprague-Dawley; Body Temperature; Neurotoxicity Syndromes; Hyperthermia, Induced
PubMed: 37224751
DOI: 10.1016/j.biopha.2023.114880 -
Frontiers in Endocrinology 2023Methimazole (MMI) represents the conventional therapeutic agent for Graves' disease (GD) hyperthyroidism, but MMI efficacy is limited since it marginally affects the...
INTRODUCTION
Methimazole (MMI) represents the conventional therapeutic agent for Graves' disease (GD) hyperthyroidism, but MMI efficacy is limited since it marginally affects the underlying autoimmune process. In a previous study, we randomly assigned 42 newly diagnosed GD patients with insufficient vitamin D (VitD) and selenium (Se) levels to treatment with MMI alone (standard) or combined with selenomethionine and cholecalciferol (intervention) and observed a prompter resolution of hyperthyroidism in the intervention group.
METHODS
In the present study, we aimed to explore changes in peripheral T regulatory (Treg) and circulating natural killer (NK) cell frequency, circulating NK cell subset distribution and function, during treatment.
RESULTS
At baseline, circulating total CD3CD56NK cells and CD56 NK cells were significantly higher in GD patients than in healthy controls (HC) (15.7 ± 9.6% vs 9.9 ± 5.6%, p=0.001; 12.2 ± 10.3% vs 7.3 ± 4.1%, p=0.02, respectively); no differences emerged in Treg cell frequency. Frequencies of total NK cells and CD56 NK cells expressing the activation marker CD69 were significantly higher in GD patients than in HC, while total NK cells and CD56 NK cells expressing CD161 (inhibitory receptor) were significantly lower. When co-cultured with the K562 target cell, NK cells from GD patients had a significantly lower degranulation ability compared to HC (p<0.001). Following 6 months of treatment, NK cells decreased in both the intervention and MMI-alone groups, but significantly more in the intervention group (total NK: -10.3%, CI 95% -15.8; -4.8% vs -3.6%, CI 95% -9; 1.8%, p=0.09 and CD56 NK cells: -6.5%, CI 95% -10.1; -3 vs -0.9%, CI 95% -4.4; 2%, p=0.03). Compared to baseline, CD69 NK cells significantly decreased, while degranulation ability slightly improved, although no differences emerged between the two treatment groups. Compared to baseline, Treg cell frequency increased exclusively in the intervention group (+1.1%, CI 95% 0.4; 1.7%).
DISCUSSION
This pilot study suggested that VitD and Se supplementation, in GD patients receiving MMI treatment, modulates Treg and NK cell frequency, favoring a more pronounced reduction of NK cells and the increase of Treg cells, compared to MMI alone. Even if further studies are needed, it is possible to speculate that this immunomodulatory action might have facilitated the prompter and better control of hyperthyroidism in the supplemented group observed in the previous study.
Topics: Humans; Methimazole; Antithyroid Agents; Selenium; Vitamin D; Pilot Projects; Graves Disease; Hyperthyroidism; Vitamins; Dietary Supplements
PubMed: 37124743
DOI: 10.3389/fendo.2023.1145811 -
Toxicology Letters Jan 2022Disruption of the thyroid hormone system during development can impair brain development and cause irreversible damage. Some thyroid hormone system disruptors act by...
Disruption of the thyroid hormone system during development can impair brain development and cause irreversible damage. Some thyroid hormone system disruptors act by inhibiting the thyroperoxidase (TPO) enzyme, which is key to thyroid hormone synthesis. For the potent TPO-inhibiting drug propylthiouracil (PTU) this has been shown to result in thyroid hormone system disruption and altered brain development in animal studies. However, an outstanding question is which chemicals beside PTU can cause similar effects on brain development and to what degree thyroid hormone insufficiency must be induced to be able to measure adverse effects in rats and their offspring. To start answering these questions, we performed a perinatal exposure study in pregnant rats with two TPO-inhibitors: the drug methimazole (MMI) and the triazole herbicide amitrole. The study involved maternal exposure from gestational day 7 through to postnatal day 22, to MMI (8 and 16 mg/kg body weight/day) or amitrole (25 and 50 mg/kg body weight/day). Both MMI and amitrole reduced serum T4 concentrations in a dose-dependent manner in dams and offspring, with a strong activation of the hypothalamic-pituitary-thyroid axis. This reduction in serum T4 led to decreased thyroid hormone-mediated gene expression in the offspring's brains and caused adverse effects on brain function, seen as hyperactivity and decreased habituation in preweaning pups. These dose-dependent effects induced by MMI and amitrole are largely the same as those observed with PTU. This demonstrates that potent TPO-inhibitors can induce effects on brain development in rats and that these effects are driven by T4 deficiency. This knowledge will aid the identification of TPO-inhibiting thyroid hormone system disruptors in a regulatory context and can serve as a starting point in search of more sensitive markers of developmental thyroid hormone system disruption.
Topics: Amitrole; Animals; Animals, Newborn; Antithyroid Agents; Disease Models, Animal; Enzyme Inhibitors; Female; Maternal Exposure; Methimazole; Motor Activity; Neurotoxicity Syndromes; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Signal Transduction; Thyroid Function Tests; Thyroid Gland
PubMed: 34757178
DOI: 10.1016/j.toxlet.2021.10.010 -
BMC Endocrine Disorders Jun 2021Thyrotoxicosis is the state of thyroid hormone excess. But, in sub-Saharan Africa (SSA), specifically Northern Ethiopia, scientific evidence about thyrotoxicosis and its...
BACKGROUND
Thyrotoxicosis is the state of thyroid hormone excess. But, in sub-Saharan Africa (SSA), specifically Northern Ethiopia, scientific evidence about thyrotoxicosis and its cardiac complications like dilated cardiomyopathy is limited. Therefore, this study aimed to explore the thyrotoxicosis presentation and management and identify factors associated with dilated cardiomyopathy in a tertiary hospital in Northern Ethiopia.
METHODS
An institution-based cross-sectional study was conducted in Ayder Comprehensive Specialized Hospital from 2017 to 2018. Data from 200 thyrotoxicosis cases were collected using a structured questionnaire. After describing variables, logistic regression was conducted to identify independent predictors of dilated cardiomyopathy. Statistical significance was declared at p < 0.05.
RESULTS
Mean age at presentation of thyrotoxicosis was 45 years and females accounted for 89 % of the cases. The most frequent etiology was multinodular toxic goiter (51.5 %). As well, the most common symptoms and signs were palpitation and goiter respectively. Thyroid storm occurred in 6 % of the cases. Out of 89 patients subjected to echocardiography, 35 (39.3 %) of them had dilated cardiomyopathy. And, the odds of dilated cardiomyopathy were higher in patients who had atrial fibrillation (AOR = 15.95, 95 % CI:5.89-38.16, p = 0.001) and tachycardia (AOR = 2.73, 95 % CI:1.04-7.15, p = 0.040). All patients took propylthiouracil and 13.0 % of them experienced its side effects. Concerning β-blockers, propranolol was the most commonly (78.5 % of the cases) used drug followed by atenolol (15.0 %). Six patients underwent surgery.
CONCLUSIONS
In developing countries like Ethiopia, patients with thyrotoxicosis have no access to methimazole which is the first-line anti-thyroid drug. Besides, they greatly suffer from dilated cardiomyopathy (due to late presentation) and side effects of propylthiouracil. Therefore, we recommend that patients should get adequate health information about thyrotoxicosis and anti-thyroid drugs including their side effects. Additionally, hospitals and other concerned bodies should also avail of TSH tests and methimazole at an affordable cost. Furthermore, community awareness about iodized salt and iodine-rich foods should be enhanced.
Topics: Adolescent; Adult; Antithyroid Agents; Cardiomyopathy, Dilated; Cross-Sectional Studies; Developing Countries; Ethiopia; Female; Goiter, Nodular; Humans; Iodine; Male; Methimazole; Middle Aged; Sodium Chloride, Dietary; Thyrotoxicosis; Young Adult
PubMed: 34182968
DOI: 10.1186/s12902-021-00796-5 -
Chemical Research in Toxicology Dec 2021Methimazole (MMI) is a widely used antithyroid drug, but it can cause hepatotoxicity by unknown mechanisms. Previous studies showed that the hepatic metabolism of MMI...
Methimazole (MMI) is a widely used antithyroid drug, but it can cause hepatotoxicity by unknown mechanisms. Previous studies showed that the hepatic metabolism of MMI produces -methylthiourea, leading to liver damage. However, the specific enzyme responsible for the production of the toxic metabolite -methylthiourea is still unclear. In this study, we screened cytochromes P450 (CYPs) in -methylthiourea production from MMI. CYP2A6 was identified as the key enzyme in catalyzing MMI metabolism to produce -methylthiourea. When mice were pretreated with a CYP2A6 inhibitor, formation of -methylthiourea from MMI was remarkably reduced. Consistently, the CYP2A6 inhibitor prevented MMI-induced hepatotoxicity. These results demonstrated that CYP2A6 is essential in MMI bioactivation and hepatotoxicity.
Topics: Animals; Cytochrome P-450 CYP2A6; Cytochrome P-450 Enzyme Inhibitors; Humans; Liver; Male; Methimazole; Mice; Molecular Structure; Recombinant Proteins; Thiourea; Tranylcypromine
PubMed: 34788025
DOI: 10.1021/acs.chemrestox.1c00300 -
Mediators of Inflammation 2020Astrocytes respond to central nervous system (CNS) insults with varieties of changes, such as cellular hypertrophy, migration, proliferation, scar formation, and...
Astrocytes respond to central nervous system (CNS) insults with varieties of changes, such as cellular hypertrophy, migration, proliferation, scar formation, and upregulation of glial fibrillary acidic protein (GFAP) expression. While scar formation plays a very important role in wound healing and prevents further bleeding by forming a physical barrier, it is also one of key features of CNS injury, resulting in glial scar formation (astrogliosis), which is closely related to treatment resistant epilepsy, chronic pain, and other devastating diseases. Therefore, slowing the astrocytic activation process may give a time window of axonal growth after the CNS injury. However, the underlying mechanism of astrocytic activation remains unclear, and there is no effective therapeutic strategy to attenuate the activation process. Here, we found that methimazole could effectively inhibit the GFAP expression in physiological and pathological conditions. Moreover, we scratched primary cultures of cerebral cortical astrocytes with and without methimazole pretreatment and investigated whether methimazole could slow the healing process in these cultures. We found that methimazole could inhibit the GFAP protein expression in scratched astrocytes and prolong the latency of wound healing in cultures. We also measured the phosphorylation of extracellular signal-regulated kinase (ERK) in these cultures and found that methimazole could significantly inhibit the scratch-induced GFAP upregulation. For the first time, our study demonstrated that methimazole might be a possible compound that could inhibit the astrocytic activation following CNS injury by reducing the ERK phosphorylation in astrocytes.
Topics: Animals; Astrocytes; Cell Movement; Cells, Cultured; Chondroitin Sulfate Proteoglycans; Cytokines; Extracellular Signal-Regulated MAP Kinases; Glial Fibrillary Acidic Protein; JNK Mitogen-Activated Protein Kinases; Methimazole; Mice; Mice, Inbred ICR; Wound Healing
PubMed: 32351321
DOI: 10.1155/2020/4027470 -
BMJ Case Reports Feb 2017Antithyroid arthritis syndrome is a constellation of symptoms of myalgia, arthralgia, arthritis, fever and rash associated with the use of antithyroid medications. We...
Antithyroid arthritis syndrome is a constellation of symptoms of myalgia, arthralgia, arthritis, fever and rash associated with the use of antithyroid medications. We report a case of a patient with severe hyperthyroidism likely secondary to Graves' disease who presented with the abovementioned symptoms after being treated with methimazole (antithyroid medication). Our aim is to increase awareness regarding this uncommon but disabilitating and life-threatening adverse effect of antithyroid medications among clinicians. We also discuss the proposed pathophysiology for this immunological reaction as well as management options in these patients.
Topics: Antithyroid Agents; Arthralgia; Arthritis; Drug Eruptions; Female; Fever; Humans; Hyperthyroidism; Methimazole; Middle Aged; Syndrome
PubMed: 28242803
DOI: 10.1136/bcr-2016-218459 -
International Journal of Biological... Oct 2018Human flavin-containing monooxygenase isoform 3 (hFMO3) is an important hepatic drug-metabolizing enzyme, catalyzing the monooxygenation of nucleophilic...
Human flavin-containing monooxygenase isoform 3 (hFMO3) is an important hepatic drug-metabolizing enzyme, catalyzing the monooxygenation of nucleophilic heteroatom-containing xenobiotics. Based on the structure of bacterial FMO, it is proposed that a conserved asparagine is involved in both NADP(H) and substrate binding. In order to explore the role of this amino acid in hFMO3, two mutants were constructed. In the case of N61Q, increasing the steric hindrance above the flavin N5-C4a causes poor NADP(H) binding, destabilizing the catalytic FAD intermediate, whereas the introduction of a negatively charged residue, N61D, interferes mainly with catalytic intermediate formation and its stability. To better understand the substrate-enzyme interaction, in vitro as well as in silico experiments were carried out with methimazole as substrate. Methimazole is a high-affinity substrate of hFMO3 and can competitively suppress the metabolism of other compounds. Our results demonstrate that methimazole Pi-stacks above the isoalloxazine ring of FAD in hFMO3, in a similar way to indole binding to the bacterial FMO. However, for hFMO3 indole is found to act as a non-substrate competitive inhibitor. Finally, understanding the binding mode of methimazole and indole could be advantageous for development of hFMO3 inhibitors, currently investigated as a possible treatment strategy for atherosclerosis.
Topics: Amino Acids; Atherosclerosis; Catalysis; Computer Simulation; Flavins; Humans; Indoles; Methimazole; NADP; Oxygenases; Protein Binding; Substrate Specificity
PubMed: 29959003
DOI: 10.1016/j.ijbiomac.2018.06.104